Method of forming a lock knot for coil springs



Oct. 3, 1967 KAlSER 3,344,813

METHOD OF FORMING A LOCK KNOT FOR COIL SPRINGS Filed April 13, 1964 6Sheets-Sheet 1 INVENTOR M. KAISER 3,344,813

METHOD OF FORMING A LOOK KNOT FOR COIL SPRINGS 3 Sheets-Sheet 2 E m QjjF j Oct. 3, 1967 Filed April 15. 1964 E a i i i 4 INVENTOR.

M. KAISER 3,344,813

METHOD OF FORMING A LOCK KNOT FOR COIL SPRINGS Oct. 3, 1967 3Sheets-Sheet 3 Filed April 13. 1964 INVENTOR United States Patent3,344,813 METHOD OF FORMING A LOCK KNOT FOR COIL SPRINGS Martin Kaiser,66 Spencer Ave., Toronto 3, Ontario, Canada Filed Apr. 13, 1964, Ser.No. 361,929 Claims. (Cl. 140-101) This invention relates to a method offorming a lock knot on a coil spring knotting machine wherein a knottingpinion is used to form the free end of the coil spring about an adjacentwinding to lock the end of the coil spring.

Conventional coil knotting machines utilize the method of forming theknot comprising the steps of securing the coil spring in positionwhereafter the free end of the coil spring is bent inwardly and coiledabout the adjacent coil winding for approximately three turns. Withproperly adjusted machines a reasonably tight coil is produced whichhowever has some tendency to slip on the adjacent winding whereby theend of the coil spring can become larger or smaller. This is a seriousdisadvantage since in the manufacture of furniture spring cashions,mattresses and the like it is desirable to have dimensional stability inthe individual coil springs in order that a completed coil assembly willfall within specified dimensional limits.

The coiling of the knot about the adjacent winding is normallyaccomplished by means of a knotting pinion gear which is placed aboutthe adjacent winding whereafter a spur on the gear picks up the tail endof the coil and winds it about the adjacent winding to form the knot.This gear however soon becomes worn and produces a loose knot whichresults in an unacceptable coil spring. Thus frequent replacing of theknotting pinion is required in order to produce even reasonablyacceptable coil springs.

In the present invention however means are provided for forming a knotwhich is locked securely in position in a positive manner, whereby anacceptable coil spring is produced. It is therefore an object of thepresent invention to provide a method of forming a lock knot on a coilspring, whereby even with a slightly worn knotting pinion an acceptableknot can still be produced.

It is a further object of the present invention to provide a method offorming a lock knot on a coil spring wherein the knot is tensionedagainst restraining bends on the adjacent coil, thereby to ensurecontinuous positive attachment of the knot on the coil in order toensure dimensional stability of the coil spring at all times.

In the present invention three bends are formed in the coil at the knotlocation, whereby the knot is restrained from movement along theadjacent coil thus the coil end is maintained at one constant diameterand further if desired the knot may be wound in an open manner where-.after it can be compressed and held thus by the bends in the adjacentcoil winding, whereby the knot is under tension at all times.

Other objects and features of the invention will be apparent from thefollowing detailed description and accompanying drawings in which likenumerals refer to like parts throughout the various views.

In the drawings:

FIG. 1 is a front elevation of apparatus for carrying out the steps ofthe present invention;

FIG. 2 is a section along the line 2-2 of FIG. 1;

FIG. 3 is an elevation view of a portion of the apparatus as illustratedin FIG. 1 and shows the reverse side thereof;

FIG. 4 is a fragmentary view of a portion of the apparatus asillustrated in FIG. 1 taken in the direction of the arrow 4;

ice

FIG. 5 is an end elevation of a knotting pinion for use with the presentinvention;

FIG. 6 is a side elevation of the knotting pinion as shown in FIG. 5;

FIG. 7 is a fragmentary view of a portion of the apparatus for use withthe present invention and particularly illustrates means for providingthe last 'bend in the coil;

FIG. 8 is a fragmentary view of a knot formed according to the presentinvention in an anti-clockwise direction;

FIG. 9 is a fragmentary view of a knot formed according to the presentinvention in a clockwise direction;

FIG. 10 shows the coil spring placed in the notch 42;

FIG. 11 shows the coil spring in place, in the knotting pinion in theslit 39, ready for the winding action;

FIG. 12 shows the pinion 36 ready to engage the wire 21 to start thewinding;

FIG. 13 shows the coil spring 21 after the pinion 36 has wound the wirefor one half turn;

FIG. 14 shows the coil spring 21 after one and a half turns; and

FIG. 15 shows the coil spring 21 after the full two and a half turns.

With reference to FIG. 1, FIG. 2, and FIG. 3 apparatus for carrying outthe steps of the invention this apparatus being adaptable for use inwidely used automotive spring coiling machines is illustrated andcomprises a knotting machine indicated generally as 11 having asupporting base 12 onto which is secured a holding die 13 which isadapted to support a coil spring 14 thereon.

A gripper head 15 slidably supported in guide 16 and 17 is adapted forreciprocal movement toward and away from die 13 and as will be seen inFIG. 4 the head 15 is adapted to secure the coil spring 14 in twopositions, in the upper position indicated as 18, the adjacent coil 19(shown in phantom) is held, at the lower position indicated as 20, thetail end 21 of the coil spring 14 is held.

A rocking arm 22 supported on pin 23 is operated by a cam 24 on the camshaft 25. The cam shaft 25 is operated from the mechanism of the coilknotting machine which is conventional and well known in the art. Theshaft 25 is suitably timed by providing the necessary gearing betweenthe normal driving shaft within the coil knotting machine. Anintermediate sliding member 26 is slidably positioned on the supports 27and 28 and is operably connected to the rocking arm 22 and the gripperhead 15 whereby upon rotation of the cam 24 the gripper head 15 iscaused to move into position against the die 13 to ensure the coilspring 14 as noted.

A cradle 29 is pivotally supported on a shaft 30 and is adapted to pivotinto an operable position by means of the cam 31 mounted on shaft 32. Itshould be noted that the shaft 32 is by suitable gearing connected intiming with the cam shaft 25 by well known and conventional means.

Cradle 29 has a driving gear 33 which is secured to the shaft 30 androtates therewith and during the forming of a single knot on the coilgear 33 makes one revolu tion the position of start and stop beingmaintained by the pawl 34 dropping into a recess 35 on the hub of thegear 33.

Cradle 29 also rotatably supports a knotting pinion 36 which isillustrated in detail in FIGS. 5 and 6. Knotting pinion 36 comprises abody portion 37 provided with a conical inner surface indicated as 38reading to a slot indicated as 39 at one end thereof. The bottom end ofthe slot 39 at the center of the pinion as indicated at 40 is adapted tobe a comparatively close fit on the diameter of the wire of spring 14whereby upon upward movement of the cradle 29 the wire of the spring 14will be securely gripped by the knotting pinion 36. Pinion 36 isprovided with a wire catching portion 41 which engages 3 with the tailend 21 of the spring 14 in the well known and conventional manner.

Cradle 29 is also provided with a notch on the side plate 42a at42whereby upon upward movement of the cradle 29 the tail end 21 is securedby the notch and bent inwardly towards the center of the coil spring 14substantially at right angles to the adjacent coil 19.

A hammer 43 is slidably positioned in guides 44 and 45 and is operablyconnected with the cam 46 by means of the rocking arm 47 whereby uponrotation of the cam shaft hammer 43 is caused to move inwardly. As shownin FIG. 7 upon the hammer 43 moving inwardly into position within thecone surface 38 of the knotting pinion 36 the end of the hammer 43 beingprovided with a small groove as indicated at 48 engages the adjacentcoil 19 whereby a bend 54 is formed therein.

In use the present method is first to support the spring 14 onto thefixture 13 whereafter the gripper 15 is moved into position to securethe adjacent coil winding 19 and to secure the tail end 21 substantiallyas shown in FIG. 4.

The cradle 29 is then caused to move upwardly whereby the tail end 21engages on the notch 42 of the cradle and is bent substantially at rightangles to the adjacent coil winding 19 and is brought into engagementwith the projecting catching portion 41 of the knotting pinion 36, theadjacent winding 19 being positioned into the slot 39 that is located ata slight angle with direction of movement of cradle 29. As the cradle 29moves upwardly the adjacent coil winding 19 is bent backwards towardsthe base of the coil spring 14 by means of the edge 49 of the knottingpinion 36 impinging thereon, thereby to form a first bend 50 asillustrated in FIG. 8 that shows a knot formed anti-clockwise about coil19, knot 53 proceeding under coil 19 on the adjacent coil winding 19.

FIG. 9 shows a knot 53a formed in clockwise direction over coil spring19a, knot 53a proceeding over coil 19a. The present invention is theonly device that will produce such a clockwise knot.

Shaft is then rotated to cause the knotting pinion 36 to rotateapproximately one-half turn whereby the tail 21 is wrapped about theadjacent winding 19. The indentation of selective size indicated as 51in FIG. 2 on the cam 31 allows the cradle 29 to move downwardly wherebythe knotting pinion 36 bends the adjacent coil winding 19 away from thecenter of the coil thereby to form complete a second bend 52 asillustrated in FIG. 8 and at the same time make the base perfectlyconcentric. Hereafter the gear 33 causes the knotting pinion to rotateapproximately two and one-half turns more whereby the completed knot asshown in FIG. 8 as 53 is formed upon knotting gear having rotated a full3 turns. Before release of the coil spring 14 or before completion ofthe knot, the cam 46, operating through the arm 47, causes the hammer 43to move forward and strike the adjacent winding 19 as shown in FIG. 7 tobend the winding toward the base of the coil spring 19 to form the thirdbend 54 as shown in FIG. 8.

From the foregoing it will be seen that the method of the presentinvention provides a knot which is securely held on the winding of thecoil spring and that a substantially uniformly round spring is produced.The knot 53 as shown in FIG. 8 is held from movement by means of thebends 52 and 54 and the bend ensures that the completed end coil willlie in a plane substantially at right angles to the axis of the coilspring 14.

A further improvement is provided in that the shaft 30 shown in FIG. 3(supported on bearing supports 55 and 56) can move from side to side. Tothis end a cam face 57 is provided on the end of the shaft 30 andadapted to bear against a roller 58 mounted on a support 59. As windingof the knot 53 as shown in FIG. 8 progresses, the natural resilience inthe material of the spring 14 will force the shaft against the roller58. If desired a second cam 60 may also be placed at the opposite end ofthe shaft 30 whereby the movement of the shaft 30 will be independent ofthe resilience of the spring material and that further the coil spacingof the knot 53 can be controlled. Thus in this manner the coil of theknot 53 may be wound in a close or open manner to begin with whereafterduring the end of the winding it may be compressed into a tighter coilwhereby upon forming of third bend 54 the knot 53 will be heldcompressed. Also the knot 53 may be wound in an open manner whereaftercompletion of the knot, it can be compressed by suitable movement of theshaft 30 to form a tighter knot, whereafter the third bend 54 can beformed to secure the knot in the compressed condition, which may beformed before completion of the knot to accentuate compression thereon.

From the foregoing it will be seen that the method of the presentinvention is first to form a bend in the adjacent coil windin-gwhereafter the knot is partially formed on the winding and a second bendis provided to form a means for locking one end of the knot. Furtherwinding of the knot either open to be compressed or closed to be tightlywound on the adjacent winding is accomplished until approximately twoand a half further turns have been completed. A third bend is thenformed on the adjacent winding to securely lock the knot in position.

It will be further understood that although specific embodiments of theinvention have herein been described and illustrated, the invention alsocontemplates such variations as may fall within the scope of theappended claims.

The embodiments of this invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A method of forming a lock knot on a coil spring by means of aknotting pinion, said pinion having a radial slit extending from thecenter to the peripheral edge thereof; and means to control same andcomprising the steps of: securing said coil spring at one end thereofand leaving a tail end of said coil spring free; bending the tail ofsaid coil inwards towards the center of said coil until said tail issubstantially atright angles to the adjacent coil winding; moving saidknotting pinion with said radial slit at a slight angle to the plane ofthe end coil of said coil spring, into position about said adjacentwinding backwards towards the base of said coil to form a first andpartially second bend; rotating said knotting pinion to wind said tailabout said adjacent coil winding for at least one-half turn; moving saidknotting pinion away from said coil thereby to bend said winding in adirection away from the center of said coil, thereby to complete saidsecond bend and form said end coil into a circular configuration;further winding said tail about said adjacent coil winding for a totalof approximately two and a half turns; and bending said coil close tosaid turns in a direction toward the base of said coil, thereby to forma third bend to secure said turns and to form said lock knot.

2. A method of forming a lock knot on a coil spring by means of aknotting pinion and means to control same and comprising the steps of:securing said coil spring at one end thereof and leaving the tail free;bending a tail end of said coil spring in towards the center of saidcoil until said tail is substantially at right angles to the adjacentcoil winding; moving said knotting pinion into position about saidadjacent winding, thereby to bend said winding backwards toward the baseof said coil to form a first bend; winding said tail about said adjacentcoil winding for at least one-half turn; moving said knotting pinionaway from said adjacent winding thereby to bend said winding in adirection away from the center of said coil, thereby to form a secondbend; further rotating said knotting pinion to wind said tail about saidadjacent coil winding first in an open manner and then in a closedmanner, thereby to form a compressed coil of approximately two and ahalf turns; and bending said adjacent winding close to said turns in adirection toward the base of said coil, thereby to form a third bend tosecure said turns and to form said lock knot.

3. A method of forming a lock knot on a coil spring by means of aknotting pinion and means to control same and comprising the steps of:securing said coil spring at one end thereof and leaving the tail free;bending a tail end of said coil spring in towards the center of saidcoil until said tail is substantially at right angles to the adjacentcoil winding; moving said knotting pinion into position about saidadjacent winding, thereby to bend said winding backwards toward the baseof said coil to form a first bend; rotating said knotting pinion to windsaid tail about said adjacent coil winding for at least one-half turn;moving said knotting pinion away from said adjacent winding thereby tobend said winding in a direction away from the center of said coil,thereby to form a second bend; further winding said tail about saidadjacent coil winding first in an open manner and then in a closedmanner, thereby to form a compressed coil of approximately two and ahalf turns; and striking said adjacent winding close to said turns in adirection toward said coil base, thereby to form a third bend and tohold said compressed coil in position.

4. A method of forming a lock knot on a coil spring by means of aknotting pinion and means to control same and comprising the steps of:securing said coil spring at one end thereof and leaving a tail endthereof free; bending the tail of the coil in towards the center of saidcoil until said tail is substantially at right angles to the adjacentcoil winding; moving said knotting pinion into position about saidadjacent winding, thereby to bend said winding backwards toward the baseof said coil to form a first bend; rotating said knotting pinion to windsaid tail about said adjacent coil winding for at least one-half turn;moving said knotting pinion away from said adjacent winding thereby tobend said winding in a direction away from the center of said coil,thereby to form a second bend; further winding said tail about saidadjacent coil winding in an open manner to form a total of approximatelytwo and a half turns; compressing said turns; and striking said adjacentwinding close to said turns in a direction toward said coil base,thereby to form a third bend and to hold said compressed coil inposition.

5 A method of forming a lock knot on a coil spring by means of aknotting pinion, said pinion having a radial slit extending from thecenter to the peripheral edge thereof, and means to control same, andcomprising the steps of securing said coil spring at one end thereof,and leaving the tail 'free; bending said tail of the coil inwardstowards the center of said coil until said tail is substantially atright angles to the adjacent coil winding, moving said knotting pinionwith said radial slit at a slight angle to the plane of said coil springinto position about said adjacent winding, by rotating said knottingpinion, winding said tail about said adjacent coil winding, for half aturn, moving said knotting pinion in a direction away from the center ofthe coil, thereby forming a bend of the said adjacent coil winding,rotating said knotting pinion further, thereby winding said tail aroundsaid coil winding for two and one-half turns forming said lock knot,bending said adjacent coil close to said winding thereby to secure saidlock knot in place, and striking said lock knot toward said coil basethereby to compress said lock knot to hold it in place.

References Cited UNITED STATES PATENTS 2,230,110 1/1941 Gleason 1012,527,325 10/1950 Myers 140-101 3,043,347 7/ 1962 Piliero 140101 CHARLESW. LANHAM, Primary Examiner.

L. A. LARSON, Assistant Examiner.

1. A METHOD OF FORMING A LOCK KNOT ON A COIL SPRING BY MEANS OF AKNOTTING PINION, SAID PINION HAVING A RADIAL SLIT EXTENDING FROM THECENTER TO THE PERIPHERAL EDGE THEREOF; AND MEANS TO CONTROL SAME ANDCOMPRISING THE STEPS OF: SECURING SAID COIL SPRING AT ONE END THEREOFAND LEAVING A TAIL END OF SAID COIL SPRING FREE; BENDING THE TAIL OFSAID COIL INWARDS TOWARD THE CENTER OF SAID COIL UNTIL SAID TAIL ISSUBSTANTIALLY AT RIGHT ANGLES TO THE ADJACENT COIL WINDING; MOVING SAIDKNOTTING PINION WITH SAID RADIAL SLIT AT A SLIGHT ANGLE TO THE PLANE OFTHE END COIL OF SAID COIL SPRING, INTO POSITION ABOUT SAID ADJACENTWINDING BACKWARDS TOWARD THE BASE OF SAID COIL TO FORM A FIRST ANDPARTIALLY SECOND BEND; ROTATING SAID KNOTTING PINION TO WIND SAID ABOUTSAID ADJACENT COIL WINDING FOR AT